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"基于Android开发的外文文献(完整资料)" Android 作为一个基于 Java 的操作系统,它运行在 Linux 2.6 内核上。该系统非常轻便且功能强大。Android 应用程序可以使用 Java 开发,并且可以轻松地移植到新的平台上。 Android 的一些特点包括: 1. 加速的 3D 图形引擎(基于硬件支持) 2. 数据库支持powered by SQLite 3. 集成的网页浏览器 Android 的用户界面(UI)开发可以通过两种方式实现:一种是使用传统的编程方式,直接在程序代码中处理用户界面;另一种是使用基于 XML 的用户界面布局。XML 布局是一种新的概念,对于桌面开发者来说可能是新的。 Android 的架构使得第三方应用程序拥有与系统应用程序相同的执行优先级,这是一个 major 的变化,相比于大多数系统,这些系统通常给予嵌入式系统应用程序更高的执行优先级。 每个应用程序都在自己的线程中执行,使用一个非常轻便的虚拟机。 Android 的 SDK 和 Library 也非常丰富,提供了许多有用的工具和 API,方便开发者快速开发应用程序。 Android 提供了一个功能强大且灵活的平台,方便开发者快速开发出色的应用程序。
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基于 Android 开发的外文文献
(完整资料)
(可以直接使用,可编辑 优秀版资料,欢迎下载)
Android
Android, as a system, is a Java-based operating system that ru
ns on the Linux 2。6 kernel。 The system is very lightweight a
nd full featured。 Android applications are developed us
ing Java and can be ported rather easily to the new platform. I
f you have not yet downloaded Java or are unsure about
which version you need, I detail the installation of the de
velopment environment in Chapter 2. Other features of Android
include an accelerated 3-D graphics engine (based on hardw
are support), database support powered by SQLite, and an inte
grated web browser。
If you are familiar with Java programming or are an OO
P de velop er o f a ny sort , yo u are like ly used to
programmatic user interface (UI) development—that is, UI placeme
nt which is handled directly within the program code. Android,
while recognizing and allowing for programmatic UI developm
ent, also supports the newer, XML-based UI layout. XML UI
layout is a fairly new concept to the average desktop develo
per。 I will cover both the XML UI layout and the programm
atic UI development in the supporting chapters of this book。
One of the more exciting and compelling features of An
droid is that, because of its architecture, third-party applic
ations-including those that are “home grown"—are executed
with the same system priority as those that are bundled
with the core system. This is a major departure from m
ost systems, which give embedded system apps a greater ex
ecution priority than the thread priority available to
apps created by third-party developers。 Also, each application
is exe cute d within its own thread u sin g a v ery l ight wei gh t
virtual machine.
Aside from the very generous SDK and the well—formed
libraries that are available to us to develop with, the mos
t exciting feature for Android developers is that we now hav
e access to anything the operating system has access to。 In
other words, if you want to create an application that dials the
phone, you have access to the phone's dialer; if you want to crea
te an application that utilizes the phone’s internal GPS (if e
quipped), you have access to it。 The potential for develope
rs to create dynamic and intriguing applications is now wide
open。
On top of all the features that are available from
the Android side of the equation, Google has thrown in some v
ery tantalizing features of its own. Developers of Android applica
tio n s w ill be abl e to tie t h ei r applic a tions into exi s ting Go o gle
offerings such as Google Maps and the omnipresent Google Sea
rch. Suppose you want to write an application that pulls up a
Google map of where an incoming call is emanating from,
or you want to be able to store common search results with your
contacts; the doors of possibility have been flung wide o
pen with Android。
Chapter 2 begins your journey to Android development。
You will learn the how's and why’s of using specific development
envi ronm ents or i ntegra ted d evelopment environment s
(IDE), and you will download and install the Java IDE Ecl
ipse。
Application Components
A central feature of Android is that one application can make
use of elements of other applications (provided those applicatio
ns permit it)。 For example, if your application needs to displa
y a scrolling list of images and another application has devel
oped a suitable scroller and made it available to others, y
ou can call upon that scroller to do the work, rather than
develop your own. Your application doesn’t incorporate the code
of the other application or link to it. Rather, it simply starts u
p that piece of the other application when the need arises.
For this to work, the system must be able to start an app
lication process when any part of it is needed, and instan
tiate the Java objects for that part。 Therefore, unlike applications on
most other systems, Android applications don’t have a
single entry point for everything in the application (no ma
in() function, for example). Rather, they have essential compone
nts that the system can instantiate and run as needed. There
are four types of components:
Activities
An activity presents a visual user interface for one fo
cused endeavor the user can undertake. For example, an activity might
present a list of menu items users can choose from or it might disp
l ay p h otographs a l o ng wi t h their captions. A tex t messagin g
application might have one activity that shows a list of contacts
to send messages to, a second activity to write the message
to the chosen contact, and other activities to review old
messages or change settings. Though they work toget
her to form a cohesive user interface, each activity is ind
ependent of the others. Each one is implemented as a
subclass of the Activity base class。
An application might consist of just one activity or, like t
he text messaging application just mentioned, it may contain se
veral。 What the activities are, and how many there are depe
nds, of course, on the application and its design. Typically,
one of the activities is marked as the first one that should be p
resented to the user when the application is launched。 M
oving from one activity to another is accomplished by hav
ing the current activity start the next one。
Each activity is given a default window to draw
in。 Typically, the window fills the screen, but it might be smal
ler than the screen and float on top of other windows。 An acti
vity can also make use of additional windows - for exam
ple, a pop-up dialog that calls for a user response in the midst
of the activity, or a window that presents users with vital
information when they select a particular item on—screen。
The visual content of the window is provided by a hierarchy of vi
ews — objects derived from the base View class. Each view co
ntrols a particular rectangular space within the window. Parent
views contain and organize the layout of their children. Leaf views
(those at the bottom of the hierarchy) draw in the rectangles
they c o n trol and resp o nd t o user actions d i rected at t h at s p
ace. Thus, views are where the activity's interaction with the u
ser takes place。
For example, a view might display a small image and
initiate an action when the user taps that image. Android has
a number of ready—made views that you can use - including
buttons, text fields, scroll bars, menu items, check box
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